log: follow filenames through renames (issue647) In commands.log a displayer was initialized from cmdutil.show_changeset() with the initial matchfn (which designates the specified files which only is correct in the highest revision in the range). prep() is handed the correct list of files, but displayer.show() didn't use that list but keept using the original matchfn. The matchfn argument to cmdutil.show_changeset() wasn't specified in other places and is only used in .show(), so now we give the matchfn as an optional parameter to .show(). We do however still have to detect --patch and --stat from opts in show_changeset() and let it imply a matchall, but that can now be overruled with the new .show() matchfn parameter.

% test file addition with bad case
adding a
A a
a
% test case collision on rename (issue 750)
adding a
a
committed changeset 0:07f4944404050f47db2e5c5071e0e84e7a27bba9
A: not overwriting - file exists
% test case collision between revisions (issue 912)
adding a
adding A
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
1 files updated, 0 files merged, 1 files removed, 0 files unresolved